统计问题求教

[ccc]

朋友问我几个统计方面的题。我卡壳了。高人支个招。

During the peak vacation season, an average of 3.0 guests does not show up each day to claim their reservations at the club. What is the likelihood of exactly 4 no shows today?

a) .0003
b) .1680
c) .1954
d) none of the above

 

[ccc]

According to a recent poll of adults, compared with their parents, 70 percent are better off financially. If we select 8 adults, what is the likelihood exactly 6 are better off financially than their parents?

a) .21
b) .01
c) .2965
d) none of the above

 

[Ayin_Ottawa]

朋友问我几个统计方面的题。我卡壳了。高人支个招。

During the peak vacation season, an average of 3.0 guests does not show up each day to claim their reservation at the club. What is the likelihood of exactly 4 no shows today?

a) .0003
b) .1680
c) .1954
d) none of the above

d

unable to determine from data provided

 

[ottawauser]

According to a recent poll of adults, compared with their parents, 70 percent are better off financially. If we select 8 adults, what is the likelihood exactly 6 are better off financially than their parents?

a) .21
b) .01
c) .2965
d) none of the above

b..
0.7^6*0.3^2

 

[ccc]

谢谢楼上二位！

 

[ccc]

朋友问我几个统计方面的题。我卡壳了。高人支个招。

During the peak vacation season, an average of 3.0 guests does not show up each day to claim their reservations at the club. What is the likelihood of exactly 4 no shows today?

a) .0003
b) .1680
c) .1954
d) none of the above

b) .1680

 

[ccc]

According to a recent poll of adults, compared with their parents, 70 percent are better off financially. If we select 8 adults, what is the likelihood exactly 6 are better off financially than their parents?

a) .21
b) .01
c) .2965
d) none of the above

c) .2965

 

[该出手时就出手]

c) .2965

别听他俩的。我是统计局的。

第一题套泊松分布公式，是可求的。第二题用binomial 分布公式做。前面给的答案有误，漏了binomial coefficient.

 

[闲哥]

这才是正解.

别听他俩的。我是统计局的。

第一题套泊松分布公式，是可求的。第二题用binomial 分布公式做。前面给的答案有误，漏了binomial coefficient.

关键时候还得靠人民政府啊.

 

[ccc]

别听他俩的。我是统计局的。

第一题套泊松分布公式，是可求的。第二题用binomial 分布公式做。前面给的答案有误，漏了binomial coefficient.

谢过!

您早来一步就好了。

下次再遇到这样的东东，得敲你家们去。

 

[ottawauser]

别听他俩的。我是统计局的。

第一题套泊松分布公式，是可求的。第二题用binomial 分布公式做。前面给的答案有误，漏了binomial coefficient.

Great, I got it!
0.7^6*0.3^2* (2C8)
Thanks

 

[该出手时就出手]

谢过!

您早来一步就好了。

下次再遇到这样的东东，得敲你家们去。

您的标题太不明确，俺哪知道是这种菜鸟题？

 

[ccc]

您的标题太不明确，俺哪知道是这种菜鸟题？

改正了。下次再遇到这样的难题再来。

谢谢！

 

[Hainiu]

接着算算 649 的中奖概率吧。听说 649 对上三个数字就有奖。请问：正好对上 3、4、5 个数字的概率各是多少？一个数字也对不上的概率是多少？买一次平均对上几个数字？

 

[ccc]

接着算算 649 的中奖概率吧。听说 649 对上三个数字就有奖。请问：正好对上 3、4、5 个数字的概率各是多少？一个数字也对不上的概率是多少？买一次平均对上几个数字？

六位数是头奖，这个不能忘记。